league is for two or more of its members to hie themselves to the tree in which the victim is building its nest, take up positions near that structure and begin to caw derisively. This invariably provokes the owners of the nest to attack the black villains, who do not resist, but take to their wings. The angry, swearing builders follow in hot pursuit for a short distance and then fly back to the nest. After a few minutes the crows return. Then the performance is repeated; and so on, almost ad infinitum. The result is that many pairs of birds of prey take three weeks or longer to construct a nest which they could have completed within a week had they been unmolested.

Most of the larger owls are now building nests or sitting on eggs; a few are seeking food for their offspring. As owls work on silent wing at night, they escape the attentions of the crows and the notice of the average human being. The nocturnal birds of prey of which nests are likely to be found in January are the brown fish-owl (